feat: InMemoryDocumentStore serialization

[davidberenstein1957]

Related Issues

• fixes feat: implement serialization for InMemoryDocumentStore  #7887

Proposed Changes:

Added two save_to_disk and load_from_disk functions.

How did you test it?

Added a test test_save_to_disk_and_load_from_disk

Notes for the reviewer

The test has an issue due to cls.from_dict methods somehow caching InMemoryDocumentStore.values(). I added an overwrite policy to avoid this but it is not the cleanest way. Not sure what is happening.

Checklist

• I have read the contributors guidelines and the code of conduct
• I have updated the related issue with new insights and changes
• I added unit tests and updated the docstrings
• I've used one of the conventional commit types for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test:.
• I documented my code
• I ran pre-commit hooks and fixed any issue

[coveralls]

Pull Request Test Coverage Report for Build 9570546368

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 8 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.01%) to 89.86%

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Files with Coverage Reduction	New Missed Lines	%
document_stores/in_memory/document_store.py	8	97.35%

Totals
Change from base Build 9568480998:	-0.01%
Covered Lines:	6974
Relevant Lines:	7761

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💛 - Coveralls

[davidsbatista]

LGTM!

[davidsbatista]

thanks for your contribution @davidberenstein1957 appreciated! 👍🏽